MECP2 and Rett syndrome: Furthermore, a Rett syndrome phenotype was described in a previous patient42 with a pericentric inversion in the vicinity of MECP2. We also identified a de novo variant in subject #2 that impacts an intronic or upstream (depending on the isoform) POL2 binding site within MECP2, though it is unclear if there is a change in transcript level as a result of this variant.